[time-nuts] Re: Creating a D.I.Y Rubidium Atomic Clock

[Andy Talbot]

I can only suggest on the PLL part.  Consider using an ADF5355, one of the
modern PLL chips available on ready made modules from CHina/Ebay
That is  Fractional-N synth chip, using a double Fract-N architecture and
capable of minute frequency steps, and an on-chip doubler allowing output
up to 12GHz
When supplied with a 10MHz reference, with the appropriate registers set,
it can get to within 0.0005Hz of the rubidium resonance.
The attached screenshot is my own calculation utility for this chip showing
(just one set of) values to do this.

More info on driving this PLL chip at http://g4jnt.com/Synthesizers.htm
Scroll down to ADF5355

Andy
www.g4jnt.com

[image: image.png]



On Tue, 6 Jun 2023 at 22:33, Leo Ahluwalia via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hello, my name is Leo, and I was wondering about the feasibility of
> creating a simple rubidium atomic clock at home, and good places to source
> parts for this sort of project. I was also wondering what instruments and
> specialized knowledge would be required depending on how pre-built the
> parts are, for example, the prerequisite knowledge for creating PLL(s) for
> both frequency division to provide an output and also to modulate the input
> of the microwave oscillator. Any good resources or PDFs would be greatly
> appreciated, as I am very new to frequency analysis and phase manipulation
> in general. I was also hoping to keep the cost of the project soft-line
> below 500$, though that would be assuming a decent level of precision and
> already possessing basic equipment (oscilloscope, multimeter, etc…). Safety
> is also a major concern, as I know while the intensity of the EM waves
> involved is low, the power source may or may not be. This is all of course
> assuming a basic design, where my assumption is that it will involve the
> microwaves being shot at a rubidium vapor cell which is directed towards a
> photodetector. This would then be connected up to the PLL and circuitry to
> both provide a stable standard while also modulating the microwave
> oscillator to offset any external environmental factors. I don't have a
> clear vision of what would truly be the best design for both simplicity and
> cost, though this is what I've found to be a common design in what I've
> looked at online.
>
>
> Thanks, Leo
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 15789 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20230607/42f20319/attachment.png>